lokesh gargreport

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A

SUMMER TRAINING REPORT

ON

BASIC GSM CONCEPT AND 3G EVOLUTION

Submitted as a requirement for the parial fulfillment of

Bachelors Degree from

Rajasthan Techinal University, Kota

Session 2010-2011

Submitted to: Submitted by:

Mr. manoj gupta Lokesh Kumar Garg

HOD of college Final year, ECE


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Preface

Summer training is the essential organ of healthy technical carrer.

The B.TECH course summer training helps a student in getting

acquinted with the manner in which his knowledge is being

practically used outside his institute and this is normally different

from what he has learnt from books. Hence, when the student

switches from the process of learning to that of implementing his

knowledge, he finds an abrupt change.

The need of training arises for doing things yourself, understanding

its way. Practical exposure for doing things make a person

conversant to the techicalities involved in any job. To overcome the

problem of profit and growth through the soundest utilization of

human capacities effective recruitment and selection process in first

step. If it is not done well no amount of training, supervision or

incentive make for it. In view of such benefits, impairing of

vocational training has been made as an integral part of any

academic structure.

In third year of B.TECH in Electronics and Communication my training

has been at IDEA CELLULAR LIMITED, JAIPUR. In this training I had a

knowledge about BASICGSM CONCEPT AND 3G EVOLUTION.


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Acknowledgement

Before I get into thick of the things I would like to add a few heartfelt

for the people who were part of my training in numerous ways,

people who gave unending support right from the stage the training

was conceived.

In the beginning of the report I want to give my thanks to Mr. Ritesh

Saraswat (Head of Department-Electronics and Communication) for

all his encouragement and appreciations that I have received from

him.

I am thankful to all the faculty members because in the supervision,suggestions and guidance of them I gain all the knowledge

experience. I give my thanks to Mrs. Hareeta Malani (Lect. ICT), Mrs.

Sarita Chauhan (Lect. ICT) and to Mr. Anurag Jagetia (TPO).

It gives me imense pleasure to acknlowledge my humble, sincere

gratitude to training incharge. I am indebted to all my elders and

friends for inspiring me to have my training with immense

dedication.

Lokesh kumar Garg


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Contents

1.Company profile.............................................................6

1.1 Location.........................................................................6

1.2 Profile............................................................................6

1.3 Boardof directors...........................................................7

1.4 Registered Office............................................................7

1.5 Corporate Office.............................................................7

1.6 Website..........................................................................8

2. Introduction.....................................................................9

2.1 Switching Systems..................................................................9

2.2 GSM Concept..............................................................................9

2.3 3G Evolution..............................................................................10

3.Switching Systems.............................................................11

3.1 MSC...........................................................................................12

3.2 VLR.............................................................................................14

3.3 MSC/VLR implementation.........................................................15

3.4 GMSC.........................................................................................17

3.5 GMSC implementation..............................................................17

3.6 HLR............................................................................................17

3.7 HLR implementation.................................................................18

3.8 Authentication Centre (AUC)....................................................18

3.9 AUC implementation................................................................18

3.10 Equipment Identity Register..................................................18


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3.11 Duplex Communication........................................................19

3.12 Radio Communication..........................................................20

4. Base Station System.........................................................25

4.1 Introduction...........................................................................25

4.2 BSC and Transcoder Controller..............................................26

5. Wireless concepts and Logical Channels.............................28

5.1 Frequency..............................................................................28

5.2 Channels................................................................................29

5.3 Modulation Method..............................................................30

5.4 Logical Channels....................................................................30

6. 3G Evolution....................................................................33

6.1 Introduction...........................................................................33

6.1.1 HSCSD.................................................................................34

6.1.2 GPRS...................................................................................34

6.1.3 EDGE..................................................................................35

6.2 The 3G of Mobile systems.....................................................36

6.2.1 Services...............................................................................36

6.2.2 Migration............................................................................37

7. Introduction to UMTS.....................................................39

7.1 UMTS Network Structure......................................................39

8. References.....................................................................40


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Chapter-1

Company Profile

1.1 Location

Idea Cellular Limited

Sahakar Marg

Jaipur

1.2 Profile

Idea Cellular is a leading GSM mobile services operator in India with

67 million subscribers, under brand IDEA. It is a pan India integrated

GSM operator covering the entire telephony landscape of the

country, and has NLD and ILD operations. A frontrunner in

introducing revolutionary tariff plans, IDEA Cellular has the

distinction of offering the most customer friendly and competitive

Pre Paid offerings, for the first time in India, in an increasingly

segmented market. From basic voice & Short Message Service (SMS)

services to high-end value added & GPRS services such as Blackberry,

Datacard, Mobile TV, Games etc - IDEA is seen as an innovative,

customer focused brand.

IDEA offers affordable and world-class mobile services to varied

segments of mobile users. Be it high end users, or low-end, price

sensitive consumers - IDEA's tariff plans are designed to suit

everyones pocket.


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1.3 Board of Directors

y Mr. Kumar Mangalam Birla Chairman

y Mrs. Rajashree Birla Non-Executive Director

y Dr. Rakesh Jain Non-Executive Director

y Mr. Biswajit A. Subramanian Non-Executive Director

y Mr. Juan Villalonga Navarro Non-Executive Director

y Mr. Arun Thiagarajan Independent Director

y Mr. Gian Prakash Gupta Independent Director

y Mr. Mohan Gyani Independent Director

y Ms. Tarjani Vakil Independent Director

y Mr. R.C. Bhargava Independent Director

y Mr. P. Murari Independent Director

y Mr. Sanjeev Aga Managing Director

y Dr. Shridhir Sariputta Hansa Wijayasuriya Alternate Director to

Mr. JuanVillalonga Navarro

1.4 Registered Office

Suman Tower,

Plot No. 18, Sector 11,

Gandhinagar 382 011

Gujarat

1.5 Corporate Office

Windsor, 5th Floor,

Off CST Road,

Near Vidya Nagari, Kalina,

Santacruz (East),Mumbai


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1.6 Website

http://www.ideacellular.com


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Chapter -2

Introduction

2.1 Switching systems

The switching system is responsible for call processing and

subscriber related functions. It includes following the following

parts:-

1. Mobile services Switching Centre (MSC)

2. Home Location Register (HLR)

3. Visitor Location Register (VLR)

4. Authentication Centre (AUC)

5. Equipment Identity Register (EIR)

2.2 GSM concept

GSM stands for Global Standards for Mobile Communications. The

GSM is divided into two basic components:-

1. Switching systems

2. Base station subsystem

The switching system is responsible for call processing and

subscriber related functions and the BSS is responsible for radio

related functions.


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There are two parts of BSS:

Base Station Controller

Base Transceiver Station

2.3 3G Evolution

3G network is todays the most growing technology in the

mobile network. There is a specific term related with the 3G network

i.e. UMTS (Universal Mobile Telecommunication System). The 3G

UMTS is mostly based on the GSM technical solutions due to two

reasons. Firstly, the GSM as technology dominates the market, and

secondly, investment made to GSM must be utilized as much as

possible.


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Chapter-3

Switching systems

The following picture illustrates the Switching system in

Ericssons GSM systems.


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3.1MSC

MSC stands for Mobile Switching Centre. It is the primary node

in a GSM network. It is the node which controls calls both to

MS (Mobile Stations) and from MS. The primary function of the

MSC the following:-

y Switching and call routing: a MSC controls call set-up,

supervision and release and may interact with other

nodes to successfully establish a call. This includes routingof calls from MS to other networks such as a PSTN.

y Charging: an MSC contains functions for charging mobile

calls and information about the particular charge rates to

apply to a call at any given time or for a given destination.


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y Service provisioning:supplementary services are provided

and managed by a MSC.

y Communication with HLR: the primary occasion on which

an MSC and HLR communicate is during the set up of a

call to an MS, when the HLR requests some routing

information from the MSC. In addition, the SMS service is

handled by MSCs.

y Communication with HLR: the primary occasion on which

an MSC and HLR communicate is during the set-up of a

call to an MS, when the HLR requests some routing

information from the MSC.

y Communication with VLR: associated with each MSC is a

VLR, with which it communicates for subscription

information, especially during call set-up and release.

y Control of connected BSCs: as the BSS (Base Station

Subsystem) acts as the interface between the MSs and

the SS, the MSC has the function of controlling the

primary BSS node i.e. the BSC. Each MSC may control

many BSCs depending on the volume of traffic in a

particular MSC service area. An MSC may communicate

with its BSCs during: for example, call set-up and

handovers between two BSCs.

y Direct access to Internet services: traditionally, an MSC

accessed the Internet nodes of the PSTN. However, this

function enables an MSC to communicate directly with

internet nodes, thus reducing call set-up time.


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3.2 VLR

VLR stands for Visitor Location Register. The role of a VLR in a

GSM network is to act as a temporary storage location for

subscription information for MSs which are within a particular

MSC service area. Thus, there is one VLR for each MSC service

area. This means that the MSC does not have to contact the

HLR (which may be located in another country) every time the

subscriber uses a service or changes its status.

The following occurs when MSs move into a new service area:

y The VLR checks its database to determine whether or not

it has a record for the MS.


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y When the VLR finds no record for the MS, it sends a

request to the subscribers HLR for a copy of the MSs

subscription.

y The HLR passes the information to the VLR and updates

its location information for the subscriber.

y The VLR stores its subscription information for the MS,

including the latest location and status.

3.3 MSC/VLR implementation

In Ericssons GSM systems, the MSC and VLR are integrated in

the AXE based node. The MSC-VLR interface is completely

internal within the AXE, but each is treated as a distinct and

separate function.


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3.4 GMSC


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y It stands for Gateway Mobile Switching Centre.

y Gateway functionality enables an MSC to interrogate HLR

in order to route a mobile terminating call. It is not used

in calls from MSs to any terminal other than another MS.

3.5 GMSC implementation

Any MSC in the mobile network can function as a gateway by

integration of the appropriate software and definition of HLR

interrogation information. In effect it then becomes a

GMSC/VLR.

In Ericssons GSM systems, gateway functions are provided

within the subsystems MSC. The only additional hardware

required is the hardware to interface the signalling link to the

HLR.

3.6 HLR

HLR stands for Home Location Register. The HLR is a centralised

network database that stores and manages all mobile

subscriptions belonging to a specific operator. It acts as a

permanent store for a persons subscription information until

that subscription is cancelled. The information stored includes:

y Subscriber identity(i.e. IMSI, MSISDN)

y Subscriber supplementary services

y Subscriber location information(i.e. MSC service area)

y Subscriber authentication information

3.7 HLR implementation


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The HLR can be implemented in the same network as the

MSC/VLR (i.e. MSC/VLR/HLR) or as a stand-alone database. An

MSC/VLR/HLR node is a suitable solution for a small start-up

GSM network as it saves hardware and signalling load on the

links between MSC/VLR and HLR.

3.8 Authentication Centre(AUC)

The Authentication Centre is a function to authenticate each

SIM card that attempts to connect to the GSM core network

(typically when the phone is powered on). Once the

authentication is successful, the HLR is allowed to manage the

SIM and services. An encryption key is also generated that is

used to encrypt all the wireless communications (voice, SMS

etc) between the mobile phone and the GSM core network. If

the authentication fails, then no service is possible from that

particular combination of the SIM card and mobile phone.

3.9 AUC implementation

There is a separate hardware of this in the switching systems.

3.10 Equipment Identity Register(EIR)

The EIR keeps a list of mobile phones (identified by their IMEI)

which are to be banned from the network or monitored. This is

designed to allow tracking of stolen mobile phones. In theory

all data about the stolen mobile phones should be distributedto all EIRs in the world through a Central EIR. However, there

are some countries where this is not in operation. The EIR data

does not have to change in real time, which means that this

function can be less distributed than the function of the HLR.

The EIR is a database that contains information about the


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identity of the mobile equipment that prevents calls from

stolen, unauthorized or defective mobile stations.

3.11 Duplex Communication

Simplex is communication in a one-way direction, such as AM

and FM broadcast to one or multiple receivers.Half duplex is

communication in a two-way direction. However, only one person

may talk at a time, since half duplex uses only one frequency. Duplex

is communication in a two-way direction on two frequencies. One

frequency is used to talk and the other one to listen. This is the

modern way of cellular communication.

There are two common ways to realise duplex transmission:

y Frequency Division Duplex(FDD)

In this case, frequency resources are allocated to the mobile

communication system. Some of the frequency bands are

allocated to uplink communication only, while other frequency

bands are used for downlink communication.

y Time Division Duplex(TDD)In this case, one carrier frequency band is used for uplink and

downlink communication. The transmission is organised in

time frames. In each time frame, time resources are used for

downlink transmission.


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FDD and TDD

3.12 Radio communication

There are two basic formats used in the radio communication:

analogue and digital. The commercially available analogue

format has been used since 1900, while the commercially

available digital format was introduced in 1900.

There are four basic air interface technologies used for

communication:

y Frequency Division Multiple Access (FDMA)

y Space Division Multiple Access (SDMA)

y Time Division Multiple Access (TDMA)

y Code Division Multiple Access (CDMA)

Frequency Division Multiple Access (FDMA)

The main logic behind the FDMA technology is the frequency range is

broken down into unique bandwidths and distributed to the users.

FDMA is used in cellular communications. One frequency to speak on


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and one to listen on; thus we have duplex communications. That way

multiple users can operate in a particular frequency spectrum.

FDMA

Space Division MultipleA

ccess (SDMA

)

The main idea behind SDMA is that the same frequency can be used

multiple times in the same geographical region. The geographical

region is break into smaller areas called cell. Each cell would use a

frequency different than those of its nearest neighbours to prevent

any interface.


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SDMA

Time Division Multiple Access (TDMA)

The idea behind TDMA is dividing the frequency into multipletime slices so that multiple users can access the same

frequency at the same time.


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TDMA

Code Division Multiple Access (CDMA)

In CDMA systems, several transmissions via the radio interface

take place simultaneously on the same frequency bandwidth.

The user data is combined at the transmitters side with a code,

then transmitted. In air, all transmissionget mixed. At the

receivers side, the same code is used as in the transmitters

side. The code helps the receiver to filter the the user

information of the transmitter from the incoming mixture of all

transmissions on the same frequency band and same time.


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CDMA


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Chapter-4

Base Station System

4.1 Introduction

The Base Station System (BSS) is responsible for all the radio-

related functions in the system, such as:

y Radio communication with the mobile units

y Handover of calls in progress between cellsy Management of all radio network resoures and cell

configuration data.Ericssons BSS consists of three components:

y Base Sation Controller (BSC): the BSC is the central

node within a BSS and co-ordinates the actions of

TRCs and RBSs.

y Transcoder Controller (TRC): the TRC provides the

BSS with rate adaption capabilites. This is necessarybecause the rate used over the air interface and that

used by MSC/VLR are different 33.8 kbits/s and 64

kbits/s respectively. A device, which performs the

adaption is called a transcoder.

y Radio Base Station (RBS): an RBS acts as the

interface between MSs and the network, by

providing radio coverage functions from their

antennae.


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BSS in Ericsson GSM systems

4.2 Base Station Controller and Transcoder

Controller

The Ericsson BSC product family consists of a combined

BSC/TRC and a remote BSC (without transcoders). The

transcoders are pooled, meaning they can be allocated on

demand Full rate, Half rate, Enhanced Full rate, AMR(Adaptive

Multi Rate) full rate or AMR half rate.

The two main available for implementing the TRC and BSC in

Ericssons BSS:

y BSC/TRC: a combined BSC andTRC on the same AXE. This

is suitable for medium and high capacity applications, e.g.

urban and suburban area networks. The node can handle

up to 1,020 transceivers (TRXs). 15 remote BSCs can be

supported from one BSC/TRC.

y Stand-alone BSC and stand-alone TRC: the stand-alone

BSC (without transcoders) is optimized for low and


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medium capacityapplications and is a complement to the

BSC/TRC, especially in rural and suburban areas. The

stand-alone TRC is located at the MSC/VLR to increase

transmission efficiency. A stand-alone TRC can support 16

remote BSCs.

TRC utilization and transmission rates in BSS


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Chapter-5

Wireless concepts and Logical Channels

5.1 Frequency

The following table summarizes the frequency-related specifications

each of the GSM systems. The terms used in the table are explained

in the remainder of this section.

An MS communicates with a BTS by transmitting or receiving radio

waves, which consist of electromagnetic energy. The frequency of a

radio wave is the number of times the wave oscillates per second.


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5.2 Channels

A channel is afrequency or set of frequencies which can be allocated

for the transmission, and the receipt, of information.

Communication channels of any form can be one of the following

types:

A simplex channel such as a FM radio station, uses a single frequency

in a single direction only. A duplex channel, such as that used during

a mobile call, uses two frequencies: one to the MS and one from the

MS. The direction from the MS to the network is referred to as

uplink. The direction from the network to the MS is referred to as

downlink.


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Uplink and downlink on a radio channel

5.3 Modulation Method

The modulation technique used in GSM is Gaussian Minimum Shift

Keying (GMSK) and is a form of phase modulation. This gives a bit

rate of 1.3 bits/s per Hz.

5.4 Logical Channels

All information to and from an MS must be formatted correctly, so

that the receiving device can understand the meaning of different

bits in the message.

The relationship between bursts and logical channels is shown in the

figure below.


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Logical channels and bursts


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Chapter-6

3G Evolution

6.1 Introduction

GSM has evolved to become a 3G network through several

steps to make a soft evolution. GSM is optimized for speech

and not for data and originally it only provides 9.6 kbits/s over

the air interface.

The most important steps involved in the evolution of GSM to

increase the data transfer rate are:

y High Speed Circuit Switched Data (HSCSD)

y General Packet Radio Service (GPRS)

y Enhanced Data for the GSM Evolution (EDGE)

The Evolution of GSM to 3G


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6.1.1 HSCSD

High Speed Circuit Switched Data (HSCSD) makes it possible to

use several timeslots simultaneously in circuit switched mode.

Today upto 4 timeslots can be used at the same time.

Furthermore, the maximum data rate in one of the timeslots is

increased from 9.6 kbit/s to 14.4kbit/s with the new coding

scheme. It is preferable for real time services (voice/video).

6.1.2 GPRS

The general trend in data applications is the generation of

increasingly bursty data streams. To support data streams with

higher bit rates a greater bandwidth is needed. Although

HSCSD does well on bandwidth by combining multiple

channels, it wastes scarce radio resources due to its circuit

switched nature. It therefore became necessary to introduce

packet switching in GSM networks in order to provide an

attractive bearer service for users wanting fast, efficient and

cheap access to the Internet and/or corporate intranet.

Extending GSM networks to support packet switching services

is therefore critical for operators wanting to position

themselves in the 3G telecom market.


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The GPRS architecture

GPRS is a bearer service realized by the introduction of twonew logical nodes in an existing GSM system: the SGSN (Serving

GPRS Support Node) and the GGSN (Gateway GPRS Support

Node). A new unit is introduced into existing BSCs called the

Packet Control Unit (PCU). The PCU consists of both hardware

and software with a central and regional processor.

6.1.3 EDGE

Operators deploying GSM/GPRS system have two paths from

which to choose. With the addition of EDGE to a GPRS network,

operators can introduce EGPRS (Enhanced GPRS) that offers

speed upto 384 kbit/s. EDGE stands for Enhanced Data rates for

Global Evolution, is an improved versions of GPRS and a logical

cost-effective step toward third-generation (3G) technology.

The implementation of GDGE in Ericsson GSM networks creates

minor changes in the network.

EDGE is an add on to the radio parts of GPRS, which means

GDGE requires GPRS and cannot work alone. EDGE increases

data transmission speeds upto 384 kbit/s or higher. The EDGE

standard has been defined for both circuit-switched and


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packet-switched traffic.Therefore, EDGE comprises both EGPRS

and ECSD (Enhanced Circuit-Switched Data).

6.2

The Third Generation of Mobile SystemsThe characteristic of third generation services is theinfrastructure capabilities to deliver several services in parallel

to each end user/terminal. This means subcribers to services

can carry on a voice conversation in parallel to accessing an

intranet or extranet to obtain important information or

participate in a video conferance and at the same time

exchange e-mails.

The general concepts for 3G systems are grouped under the

concept of the International Mobile Telecommunications 2000

(IMT-2000) system. This is complemented by development of

Universal Mobile Telecommunications Systems (UMTS) by ETSI.

UMTS aims to deliver wide-area/high-mobility data rates of 384

kbit/s and upto 2Mbps for local-area/low-mobility coverage.

To be able to support these bi rates, a new radio technology,

Wideband Code Division Multiple Access (WCDMA) is used.


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Mobile Multimedia Services

6.2.1 Services

Some basic planned 3G services include:

y Voice/high-quality audio

y High-speed data transmission

y E-postcard in combination with digital cameras

y Video conferencing and multimedia


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6.2.2Migration

The Migration of GSM to 3G

Going forward, GSM will continue to evolve to meet demands

for high-data through two complementary developments.

First, the existing MS-network interface has evolved to include

high bit rates for wide-area coverage, through HSCSD and

packet-switched data through GPRS that will provide

theoretical data rates upto 170 kbits/s.

Second, GSM will evolve to meet with 3G requirements by

offering data rates upto 384 kbit/s in all existing GSM

frequencies.

To reach this level of throughput, two air interfaces will co-

exist: the evolved GSM (TDMA) and the new UMTS interface

(WCDMA).


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Using dual-mode GSM/3G globel handsets with GSM providing

coverage and 3G delivering new functionality operators will be

able to fully leverage additional wideband services in their GSM

networks with full service transparency across the enormus

GSM worldwide presence.

The radio acess network will be a ditinct overlay network for

the two types of air interfaces. For the WCDMA radio access

network, some of the existing GSM concepts will be reused but

many principles and stuctures will be new. The core network

for WCDMA systems will be an evolution of todays GSM circuit

and packet switching networks. As a result the GMSC has

evolved to support circuit-switched accesses from the MS

towards either telecommunications-based networks.

Evolution of GSM to UMTS


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Chapter-7

Introduction to UMTS

7.1 UMTS Network Structure

The obvious lack of GSM systems is the bandwidth offered to

the end user. In the beginning the bandwidth offered to the

end user was reasonable, but as the technology developed, the

end user requirements increased. New services (such as

internet) became more common, so the bandwidth became

inadequate. This was the main reason for starting thespecification for the next generation cellular networks.The air

interface of the 3G should be generic, this means that the radio

part of the network should be even more functionally

separated than in the GSM. To clarify and specify this, the call

establishment related parts of the 3G network are expressed as

follows:

3G network principle diagram


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The multiple access method used between the User Equipment (UE)

and the RAN(Radio Access Network) is called Wideband Code

Division Multiple Access (WCDMA). The 3GPP is aiming to specify

open interfaces also within the RAN in order to guarantee

multivendor scenarios. Despite this, it is resonable to believe that

operators will not select a large number of suppliers for the RAN, nor

for the Core Network (CN) implementation.

In GSM, we use TDM (Time Division Multiplexing) as the transmission

method between the different network elements. For UMTS, ATM

(Asynchronous Transfer Mode) has been chosen as the transmission

method in the radio access network. The basic difference betweenTDM and ATM is that in TDM, we use timeslots for conveying

information between network elements. In ATM, on the other hand,

the data is transmitted in cells(packets) of fixed size across the

network.

3G network management layers


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References

1.en.wikipedia.org/wiki/GSM

2. www.tech-faq.com/gsm

3. en wikipedia.org/wiki/3G

4. www.mobilein.com/3G.htm

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